12/03/2010 @ 1:25PM

Slide Show: The Year's 10 Worst-Selling Cars

Smart ForTwo

Sales decline: -61%

The quirky two-seater was popular in 2008, when gas was $4 a gallon, but now that fuel prices have moderated, sales have collapsed. Penske Automotive Group, which distributes the vehicle in the U.S., is now testing Smart in Car2Go, a car-sharing concept, and plans to market an electric version soon.